Acoustic shock waves are created when a high voltage discharge spark passes between two coaxially aligned opposing electrode tips. In the presence of a fluid the energy is released by the spark which flashes the water to steam creating an acoustic wave wherein a series of such waves can pass through tissue to break up concrements within the body.
Preferably, the fluid around the electrode tips is a saline solution to enhance electro conductivity. In some electrode assemblies the fluid surrounding the tips is also charged with carbide particles to further increase conductivity. Such a device is described in U.S. Pat. No. 6,113,560 entitled “Method and Device For Generating Shock Waves For Medical Therapy, Particularly For Electro-Hydraulic Lithotripsy” issued Sep. 5, 2000.
As can easily be appreciated the spark generated by the voltage discharge can create a large amount of heat which tends to burn the tips of the opposing electrode conductors. As the tips burn, the spark gap distance increases resulting in even higher voltages to create a discharge. At some point this dramatically degrades the shock wave pulses generated rendering the electrode assembly non effective. This situation can occur in a very quick time meaning the replacement of the electrode assemblies is done after every second, third or fourth patient procedure. While these devices are adapted for rapid change over or replacement it is also noted that each assembly can cost as much as several hundred dollars.
Accordingly, the device described in U.S. Pat. No. 6,113,560 has been touted as having a longer time of useful capacity and better gap distance maintenance than other similar devices. While this is true, the replacement cost is offset by the high end price demanded for the product.
In U.S. Pat. No. 6,849,994 granted Feb. 1, 2005 in a patent entitled “Electrode Assembly for Lithotripters” the same owner of the U.S. Pat. No. 6,113,560 describes the need for refurbishing electrode assemblies used in lithotripters by providing easily replaceable tips. In that patent the inventors noted that a prior art electrode with an insulating layer required the insulating layer to be machined off the inner conductor prior to replacement of the discharge tip and then reapplication of the insulating layer, presumably by remolding the plastic insulating layer over the inner conductor. Naturally this was a labor intensive practice that was cost prohibitive. It was their idea to provide threaded replacement tips that could easily been replaced when burnt to refurbish a used electrode assembly. This, they argued, could greatly reduce replacement cost.
The present inventive method has found a simple quick and very precise method to repair those electrode assemblies without removable tips that were believed to be too costly to repair. No grinding or machining of the insulator layer was required.
The number of such used devices is extremely large and therefore an efficient repair process would be invaluable to the physicians using such a lithotripter having those types of electrode assemblies.
The following description and drawings provide a novel way in which repair of such devices is not only feasible but highly efficient.